Screen-plate.



No. 831,986. PATENTED SEPT. 25, 1906.

A. w. CRAWFORD.

SCREEN PLATE. APPLIGATION FILED AUG. 10, 1905.

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ALEXANDER w. CRAWFORD, or GIRARD, ILLINOIS.

SCREEN-PLATE.

Specification of Letters Patent.

Patented Sept. 25, 1906.

Application filed August 10, 1905. Serial No. 273,503-

To all whom it may concern:

I III, by the lumps of material following them,

Be it known that I, ALEXANDER W. CRAW- i and these following lumps ress against the FORD, a citizen of the United States, residing in Girard, in the county of Macoupin, in the State of Illinois, have invented certain new and useful Im rovements in Screen-Plates, of which the fo owing is a full, clear, and exact description, reference being had to the accompany ng drawings, forming part of this specification.

My invention relates to a screenlate for use in screening lumpy materials, an is more particularly intended for utility in screening coal, the object of the invention being to provide a screen-plate in which the lumps of material being screened will not become clogged in the perforations of the screen if they are too great in size to pass through the perforations, but are susceptible of entering partly thereinto.

Figure I is a perspective view of a fra mentof my screen-plate. Fig. 11 is an enlarged top or Ian view of'a fr ment' of the plate.

Fig. I is a lo it-ndin section taken on line- III III, Fig. IVis a crosssection taken on'line IV IV, Fig. II, looking in the direction of the arrow crossing said line.

1 designates my screenplate, which is rovided with a plurality of rforations 2, w 'ch are preferably elongated ongitudinally of the plate. Extending downwardly and rearwardly from the forward end of each perforation is an inclined runway 3, integral with the plate, that terminates in advance of the rear end of the perforation to a sufficient extent to permit of the lumps of material being screene passing through the perforations at the rear of said runways.

In the screenin o ieration in the use of my screening-plate the umps of material that are conveyed onto and along the screen-plate are brought to the perforations therein and th lum s of a corresponding to or smaller t an the wholly o n portions of the perforations readily pass t erethrough, while the lumps of greater sizethan the perforations are conveyed over the plate. In the passage of the large lumps over the plate many of them enter into the perforations, but cannot pass entirely therethrough, owing to their size. W'hen these lumps enter the rforat-ions, they are engaged, as seen the lumps of material that enter into the per forations and are not susceptible of passing therethrough may move with greater ease toward the inclined runways 3 to travel up said runways in the manner described in order that they may be dislodged from the perforations andcease to clog t em.

Another importantfeature in my screenplate to which I wish to direct particular no tice is that of the runways 3, being connected at their sides to the main body of the screenplate, thereby producing troughs in which the coal that enters into the perforations and cannot pass through the screen-plate ride upwardly to be discharged from the perfora tions. If it were not for the provision of the side lportions referred to, it would be possible for s arp portions of lumps of material being screened becoming clogged between the main body of the plate and the to sides of the runways, thereby defeating tiie purpose of said runways.

I claim as my invention A screen-plate for screening coal and similar lumpy material; the plate having perfo rations therein and being provided with straight inclined runways extending from the plate downwardly through the perforations; said runways extending approximately half the length of the perforations and having ver tic-a1 side walls extending upwardly to the 

